In a process of manufacturing an electronic component or semiconductor product, thin film formation and etching can be performed in a vacuum apparatus. In the process, the internal pressure of the vacuum apparatus is adjusted to a predetermined pressure. To measure a pressure in a process, a diaphragm-type pressure gauge is often used, which can perform accurate pressure measurement regardless of the type of gas.
For example, a diaphragm-type pressure gauge having a diaphragm structure like that disclosed in PTL 1 is configured to make a diaphragm electrode deflect in accordance with a pressure. However, since the diaphragm electrode also deflects in the direction of gravitational force, attaching the electrode while it is tilting in the direction of gravitational force will cause an error in a measurement value. In order to correct an error in a measurement value based on the attaching angle of a diaphragm-type pressure gauge, for example, PTL 2 discloses a technique of correcting a measurement value based on the value of a tilt angle.